1. Field of the Invention
This invention relates to an inkjet recording apparatus and, more particularly, to a recovery apparatus for performing recovery operations such as suction, empty suction, and wiping of the recording head.
2. Description of Related Background Art
Inkjet recording apparatuses, as known presently, effect recording such as letters and images on a sheet by discharging ink out of an inkjet recording head. The recording head may cause image defects due to inaccurate droplet discharges if ink is dried to clog the nozzle or ink stagnates around the outlet of the nozzle.
Various measures are taken conventionally in the inkjet recording apparatuses to discharge ink properly. First, orifices of the recording head are normally shut with a cap to prevent ink from drying. A preliminary discharge is made at a time of recording to remove clogging of the ink. Suction is made at every recording of a prescribed amount where the orifices are shut with the cap, thereby removing clogs in the nozzles which are unlikely to be eliminated by the preliminary discharge. Meanwhile, because ink may stagnate in the cap from the preliminary discharge, empty suction, in which suction is made in the cap while the orifices are not shut, clears the stagnation where the preliminary discharge is made in a prescribed amount. Wiping of the orifices with an elastic blade such as a rubber blade is made at every recording of a prescribed amount, thereby removing clogged ink around the orifices.
In the conventional art, the recovery operation of the recording head such as suction, empty suction, and wiping was controlled with respective timings. More specifically, the empty suction operation is included in the suction operation because the empty suction operation is unnecessary where the suction operation is made. The wiping operation is included in the empty suction operation, and namely, the wiping operation can be made solely, but wiping is also done where the empty suction operation is made. This is because wiping is necessary at the orifices since the preliminary discharge is made at the empty suction operation.
FIG. 5 is a timing chart showing an example of a relation between three recovery operations and normal values for determining the timings for the operations in a conventional recording apparatus. In FIG. 5, the time proceeds vertically, from the upper side to the lower side. Time T101 is a start time; a situation that, from the left side, all of wiping dot count, preliminary discharge amount in cap, and suction dot count is zero, is shown. Those three counters are independently operated, and a description here is made in extracting the operations active at the same time.
At time T102, since the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T103, again, where the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T104, the preliminary discharge amount in the cap is saturated and becomes the normal value 3 or more, and the empty suction is done. Because the wiping is done at the same time upon operation of the empty suction, the wiping dot count is cleared, and the recovery is restarted upon clearing the preliminary discharge amount in the cap.
At time T105, since the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T106, again, where the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T107, the preliminary discharge amount in the cap is saturated and becomes the normal value 3 or more, and the empty suction is done. Because the wiping is done at the same time upon operation of the empty suction, the wiping dot count is cleared, and the recovery is restarted upon clearing the preliminary discharge amount in the cap. Subsequently, at time T108, the suction dot count becomes the normal value 1, and the suction operation is made. The empty suction and wiping are done at the same time when the suction is made, and the preliminary discharge amount in the cap and the wiping dot count are cleared to restart the operations.
At time T109, since the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T110, again, where the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T111, the preliminary discharge amount in the cap is saturated and becomes the normal value 3 or more, and the empty suction is done. Because the wiping is done at the same time upon operation of the empty suction, the wiping dot count is cleared, and the recovery is restarted upon clearing the preliminary discharge amount in the cap.
At time T112, since the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T113, again, where the wiping dot count reaches the normal value 5, the wiping operation is made, and the wiping dot count is cleared. At time T114, the preliminary discharge amount in the cap is saturated and becomes the normal value 3 or more, and the empty suction is done. Because the wiping is done at the same time upon operation of the empty suction, the wiping dot count is cleared, and the recovery is restarted upon clearing the preliminary discharge amount in the cap. Subsequently, at time T115, the suction dot count becomes the normal value 1, and the suction operation is made. The empty suction and wiping are done at the same time when the suction is made, and the preliminary discharge amount in the cap and the wiping dot count are cleared to restart the operations.
As described above, in this prior art shown in FIG. 5, two of the recovery operations, wiping and empty suction, during time T103 to T104 and T110 to T111, are executed at the same time. Also, three of the recovery operations, wiping, empty suction, and suction, during time T106 to T108 and T113 to T115, are executed at the same time.
That is, in the prior art, the recovery operation is overly done within a very short period of time such as the empty suction being done immediately after the wiping operation is made or the head being suctioned immediately after the empty suction is made, even where the wiping operation is included in the empty suction operation and where the empty suction is included in the suction operation. Therefore, the prior art raised problems in that the processing efficiency and throughput were reduced.